AREAS
These recommendations are for high altitude areas (1600-2600
m) that include Paro, Thimphu, and parts of Wangdue, Punakha,
Tongsa, Lhuntshi and Tashigang.
VARIETIES
No.11
• Cold tolerant, high yielding, early maturing japonica
rice.
• About 90 cm tall and matures 135-145 days after sowing.
• Short bold white grains with 66% milling (head rice)
recovery.
• Difficult to thresh.
• Yields 5-7 t/ha under moderate management, but responds
to fertilizers
Local Maaps
• Cold tolerant, tall stature, long growth duration,
japonica types.
• Medium-short red grains, preferred for eating.
• Yields 2-3 t/ha under optimum management levels. Not
responsive to higher levels of fertilizer.
CROP ESTABLISHMENT
Nursery sowing
• Optimum sowing date: March or first week of April
• Seed rate: 50-60 kg/ha
• Use clean and healthy seeds.
• Seedlings can be raised using semi-dry or dry bed
methods (see leaflet on seedling production).
PREPARATION OF FIELD
Land preparation is one of the important factors that influences
rice yield. It provides good physical, chemical, and biological
conditions of the soil for optimum growth.
• Two or three ploughings are needed, followed by puddling
and levelling.
• Plough thoroughly and then flood.
• Drain the water slightly and plough, rotovate or harrow
as needed and level the field.
• A final puddling and levelling may be required just
before transplanting.
• Repair and maintenance of bunds and the incorporation
of chemical fertilizers, if any, should be done before the
final puddling.
MANURE AND FERTILIZER
Farmers routinely apply FYM to rice in the high altitude
areas. The rate of application varies widely from 5 to 20
t/ha. FYM contributes significantly to crop nutrition and
soil condition. It is desirable to encourage the use of FYM.
Our recommendation is to apply about 5-8 t/ha FYM basally,
and topdress with 35 kg N/ha 35-40 days after transplanting.
If adequate FYM is not available, apply 75:40:0 NPK kg/ha.
Half the N and all the P should be applied as the basal dose.
Topdress the remaining N 35-40 days after transplanting. For
local varieties, limit N to 50 kg/ha to prevent lodging.
TRANSPLANTING
Transplanting time: Mid-May to mid-June
Traditional random method can be used if:
• Weed pressure is expected to be low.
• Butachlor will be used.
• The terraces are narrow and small.
Line planting should be done if weeding will be carried out
with a rotary weeder.
• Use a rope to give a row spacing of 20 cm and within-row
spacing of 15-20 cm.
A plant density of 25-35 per square metre is optimum. Transplant
local varieties at a closer spacing (15 x 15 cm), as they
do not tiller well.
WEED CONTROL
Weeds are serious competitors of rice. They compete for water,
nutrients and sunlight, and reduce grain yields.
Where weed pressure is low or moderate, 2 hand weedings 20
and 40 days after transplanting are sufficient. If hand weeding
is to be done, plants should be closely spaced and the first
weeding performed no later than 30 days after transplanting.
Where weed pressure is high, use line planting and rotary
weeding. Two rotary weedings 20 and 40 days after planting
are recommended. In areas where shochum is a severe problem,
additional hand weedings may be required.
If there is no or little shochum but weed pressure is high,
Butachlor is a very effective alternative to rotary weeding.
It is applied 3-6 days after transplanting at the rate of
30-40 kg/ha of 5% "Punch" granules.
If shochum is a major problem it can be controlled by Sanbird
applied at 25-35 kg/ha 4-6 days after transplanting. Alternatively
apply NC 311 at 25-30 kg/ha.
As weeding is laborious, and the use of herbicides is undesirable,
there must be emphasis on indirect complementary weed control
methods like good land preparation, proper water management,
and use of weed-free seedbeds and seeds.
WATER MANAGEMENT
After transplanting keep the water level low for 4-7 days
until the seedlings recover. Water level should then be increased
as the crop grows ensuring adequate water from tillering to
flowering.
If the supply of water is limited, continuous flooding is
not possible. In this case irrigate at short intervals but
do not let the field become excessively dry and crack. Flowering
is the most critical stage when rice should not be exposed
to moisture stress.
Drain water from the field 10-15 days before harvest to enhance
ripening.
PLANT PROTECTION
Insect pest and diseases are normally not a major problem
in rice at high altitudes.
HARVEST
Under normal conditions harvesting begins from the first
week of October. Harvest the crop when at least 85% of the
upper portion of panicles turns straw coloured. Some leaves
and stems may still be green at grain maturity, particularly
for No.11.
Local varieties shatter very easily, and timely harvest will
minimize grain losses.
For further information contact
Mahesh Ghimiray, Field Crops Sector, RNR-RC, Bajo
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